Presently, the Army requires that military vehicles be used to provide power to charging devices which in turn are used to charge Army portable rechargeable batteries. Under current practices, a NATO standardized DC slave plug connector is directly connected to vehicle battery to transfer charge from the vehicle to the charging device.
The problem with drawing power from the vehicle in this manner is that the NATO slave connector is unregulated. As such, the charging devices will continue to draw charge from the vehicle or host battery until the charging devices are fully charged or the host battery is drained of its own charge. Since a threshold amount of charge in the vehicle battery is necessary to operate the vehicle, the unregulated transfer of charge from the vehicle battery to the charger devices may potentially leave the vehicle battery with a charge level below that necessary to operate the vehicle. This situation is often encountered in the Army in charging up the charging devices used to charge the rechargeable batteries for the portable communication equipment of Army personnel, where the charge transferring process is set up and performed while the Army personnel are engaged in duties remote from the charging site.
Although the problem discussed above may be avoided by physically disconnecting the connector from the vehicle battery before the amount of charge drained from the battery reaches a critical level, this solution requires the sacrifice of manpower from other duties in order to keep vigil during the charging process. Such a solution, therefore, is generally impractical. Hence, it is desirable to find an alternative means for preventing the over-discharge of the vehicle battery which does not rely upon human intervention, while providing power to the charging devices in accordance with Army guidelines.